There exist applications in which there is a need to provide for high density loading of non-uniformly sized items on a conveyor belt, especially from multiple input sources. The present invention fulfills that need.
In general, flat mail (also referred to as flats or mail flats) includes mail pieces from 31/2 inches by 5 inches to 15 inches by 15 inches, with thickness up to one inch and weight up to three pounds. When articles such as mail flats are to be deposited on a conveyor belt from multiple input sources, increasing the speed of the input belts and the speed of the receiving conveyor may increase throughput, but at the expense of an increased likelihood of item jams and other reliability and performance problems. Such problems are exacerbated when two or more source streams are to be loaded and merged onto a single conveyor at higher moving velocities. U.S. Pat. No. 3,491,903 issued Jan. 27, 1970 for "Induction Scheme and Automatic Loader" by R. R. Hedrick et al., U.S. Pat. No. 3,536,180 issued Oct. 27, 1970 for "Device for Collecting and Distributing Objects from a Plurality of Partial Streams" by G. Dubus, U.S. Pat. No. 3,693,486 issued Sep. 26, 1972 for "Conveyer System" by P. J. Maniaci et al., and U.S. Pat. No. 4,915,209 issued Apr. 10, 1990 for "Method for Controlling the Exact Positioning of the Items to be Sorted in an Automatic Sorting Plant" by F. Canziani attempt to provide loading or merging of items onto a single conveyor from multiple sources of input. However, none of these patents appear to be capable of performing high density loading when non-uniform sizes of items are being processed. It is therefore preferable to increase throughput by utilizing the full loading surface of (increasing the density of loading onto) the receiving conveyor, while maintaining only a minimal separation between the items being loaded to avoid jamming problems and the like. The present invention fulfills this need while avoiding unnecessary increases in transport speed.